Former Ohio State star and Boston Celtic Jared Sullinger puts up a shot during the semifinals of The Basketball Tournament, played at Coppin State University on Tuesday. Sullinger is among an increasing number of players with legitimate pro hopes playing in the TV-friendly summer event. (Doug Kapustin/For The Washington Post)

BALTIMORE — DeJuan Blair was running on a treadmill back in his home town of Pittsburgh. Here was a former NBA role player with the San Antonio Spurs, Dallas Mavericks and Washington Wizards, only 28 years old. Still in his athletic prime.

He had spent 2016 playing in China, and 2017 in the NBA G League. He was waiting for something else, when he got a call about playing for a team called Overseas Elite that was participating in The Basketball Tournament.

Sixty-four teams of various affiliations compete for a prize of $2 million in TBT. Overseas Elite, a two-time champion, will play in the final at Coppin State on Thursday night against Team Challenge ALS, which features former Gonzaga University and NBA player Austin Daye, among others.

Since Jon Mugar created the tournament in 2014, it has grown in popularity. It’s broadcast on ESPN. NBA scouts attend the games. NBA players coach some of the teams, and in recent years, there has been a rise in the number of pro players, and former NBA players, who have signed up to participate.

It’s former players like Blair, Daye and former Boston Celtics forward Jared Sullinger who are all playing to get exposure and hopefully grab another shot in the NBA. Former St. John’s guard D.J. Kennedy plays for Overseas Elite in The Basketball Tournament and was invited to Denver Nuggets training camp last year.

“I’m definitely trying to get back into the NBA,” Blair said. “The back door is always the hardest one, so you just got to keep going and keep grinding until something happens.”

None DeJuan Blair, left, battles Milwaukee’s Chris Copeland for a rebound during a 2015 NBA preseason game. (Tannen Maury/EPA)

When The Basketball Tournament kicked off three years ago, Mugar wasn’t sure what to expect, saying, “We didn’t know if NBA players would want to participate. We didn’t know if the level of play would exceed high school varsity guys who graduated three or four years ago.”

That’s not what’s happening.

In 2014, according to TBT, 33 players who’d played in the NBA signed up with hopes of participating, although they didn’t all take the floor. It grew to 86 in 2015 and skyrocketed to 186 in 2016. This year, according to TBT, 66 current and former NBA players participated in TBT, either as players or coaches, adding a sense of legitimacy to the tournament.

“These aren’t a bunch of no-names playing in this tournament,” said ESPN basketball analyst Fran Fraschilla. “These are professional athletes.”

Fraschilla offered a comparison for the level of play at TBT. He said that if college basketball is like Class AA baseball and the NBA is like the Major Leagues, then TBT is like Class AAA. And for players such as Daye, Blair and Sullinger, this tournament is an opportunity for competition.

“A lot of guys will play and a lot of guys will do individual workouts in the summer and they feel that that gets them better,” Daye said. “I don’t feel that individually working out by myself all summer is going to do anything for me. It’s going to sharpen myself and sharpen my tools, but it’s not going get my awareness, or my defensive coverages and just playing against a good defender.”

Daye also views this tournament as a way to boost his portfolio, saying that he wants to use this as a way to have opportunities at playing overseas or getting back in the NBA. Daye, who was the 15th overall pick in the 2009 NBA draft, is only 29, but has been out of the NBA since he was released by the Cleveland Cavaliers before the 2015-2016 season started.

The players who are playing in TBT are generally in their mid-to-late 20s, and have not necessarily reached their athletic peak.

“On occasion, these guys blossom in their 20s and they’re worth scouting,” Fraschilla said.

A few weeks ago, when TBT held the Super 16 round and Regional Championship in Brooklyn, Fraschilla said on air that the Brooklyn Nets had representatives at LIU Brooklyn to scout Sullinger.

Jared Sullinger attempts to score against Ivan Aska, left, and Austin Daye of Team ALS Challenge during Tuesday’s game. (Doug Kapustin/For The Washington Post)

Sullinger was a two-time all-American at Ohio State and a first-round pick by the Boston Celtics in 2012. He signed with the Toronto Raptors in 2016, and was traded to the Phoenix Suns in February, but was released the next day.

Sullinger was plagued by injuries in the NBA. He missed the last two months of his rookie season after undergoing back surgery. He missed the second half of the 2015 season with a stress fracture in his left foot. Sullinger told recently that he is using TBT to show NBA teams he is still healthy.

“For Jared, this is a job interview,” Fraschilla said. “This is a kid who’s trying to show NBA teams he’s still valuable.”

Sullinger averaged 14.5 points and nine rebounds in the first four games of the tournament. In the semifinal game at Coppin State University in Baltimore, against Daye’s team — Team Challenge ALS — Sullinger recorded 26 points and 10 rebounds, and half of his points came from the free throw line. However, Team Challenge ALS, won, 88-83, in a double-overtime thriller. Daye scored 22 points.

Not only did Sullinger and his team, Scarlet & Gray, fail to reach the championship game, but the championship game was, perhaps, a chance for Sullinger to show off for more NBA teams.

After the game, Sullinger got dressed and walked alone down a hallway at Coppin State, then he went through a door and disappeared, hoping he’d done enough to earn another NBA shot.